This shipping container was discovered upside down on the seafloor by researchers in June 2004, four months after it was lost at sea. Monterey Bay Aquarium Research Institute hide caption

itoggle caption Monterey Bay Aquarium Research Institute

A farmer stands in front of a mountain of spinach, disposed after gathering in Fukushima, Japan, on March 26. The government has banned the sale of milk, spinach and other leafy vegetables from Fukushima and neighboring prefectures. Jun Yasukawa/Yomiuri Shimbun/AP hide caption

itoggle caption Jun Yasukawa/Yomiuri Shimbun/AP

Cows that consume feed, grass or water contaminated with radioactive iodine-131 can concentrate the element in their milk. Peter Elvidge/iStockphoto.com hide caption

itoggle caption Peter Elvidge/iStockphoto.com

Mike Barlow has been installing geothermal systems for 20 years. But he says a 30 percent federal tax credit is increasing the popularity of the systems for families with modest houses. Elizabeth Shogren/NPR hide caption

itoggle caption Elizabeth Shogren/NPR

Tokyo Electric Power Co. Chairman Tsunehisa Katsumata (second from right) and other executives bow prior to a press conference at the company's headquarters in Tokyo on Wednesday. Kazuhiro Nogi/AFP/Getty Images hide caption

itoggle caption Kazuhiro Nogi/AFP/Getty Images

In 1992, 28,800 rubber ducks were lost at sea. What happened to them is the subject of Donovan Hohn's book Moby-Duck. Jose Gil/iStockphoto.com hide caption

itoggle caption Jose Gil/iStockphoto.com

Cooling towers from the Limerick Generating Station, a nuclear power plant in Pottstown, Pa., sit near a neighborhood. Environmentalists agree that in light of Japan's nuclear crisis, the U.S. should examine existing nuclear plants for safety risks. Stan Honda/AFP/Getty Images hide caption

itoggle caption Stan Honda/AFP/Getty Images

Japan Self-Defence Force officers in radiation protection suits hold a blue sheet over workers who were exposed this week to high levels of radiation at the Fukushima Dai-ichi plant. Jiji Press/AFP/Getty Images hide caption

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Nighthawks are known for their repeated "peent" call as they hunt for flying insects. Bill Bouton/Flickr hide caption

itoggle caption Bill Bouton/Flickr